mirror of https://gitlab.com/QEF/q-e.git
62 lines
1.7 KiB
Fortran
62 lines
1.7 KiB
Fortran
!
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! Copyright (C) 2001-2018 Quantum ESPRESSO group
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! This file is distributed under the terms of the
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! GNU General Public License. See the file `License'
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! in the root directory of the present distribution,
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! or http://www.gnu.org/copyleft/gpl.txt .
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!
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!
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!-----------------------------------------------------------------
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subroutine ccg_psi (lda, n, m, psi, h_diag, flag)
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!-----------------------------------------------------------------
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!! This routine gives a preconditioning to the linear system solver.
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!! The preconditioning is diagonal in reciprocal space.
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!
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USE kinds, only : DP
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USE noncollin_module, only : noncolin, npol
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implicit none
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integer :: lda, n, m, flag
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! input: the leading dimension of the psi vector
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! input: the real dimension of the vector
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! input: the number of vectors
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! input: flag=1 use h_diag, flag=-1 use conjg(h_diag)
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complex(DP) :: psi (lda*npol, m)
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! inp/out: the vector to be preconditioned
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complex(DP) :: h_diag (lda*npol, m)
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! input: the preconditioning vector
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integer :: k, i
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! counter on bands
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! counter on the elements of the vector
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!
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IF (flag == 1) THEN
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do k = 1, m
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do i = 1, n
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psi (i, k) = psi (i, k) * h_diag (i, k)
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enddo
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IF (noncolin) THEN
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do i = 1, n
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psi (i+lda, k) = psi (i+lda, k) * h_diag (i+lda, k)
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enddo
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END IF
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enddo
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ELSEIF (flag == -1) THEN
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do k = 1, m
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do i = 1, n
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psi (i, k) = psi (i, k) * CONJG(h_diag (i, k))
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enddo
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IF (noncolin) THEN
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do i = 1, n
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psi (i+lda, k) = psi (i+lda, k) * CONJG(h_diag (i+lda, k))
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enddo
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END IF
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enddo
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END IF
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!
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return
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!
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end subroutine ccg_psi
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